Wed·Dec 8, 2021Wednesday·December 8, 2021

1. 01*

   Dark matter detectors as a novel probe for light new physics

   Anirban Majumdar🇮🇳 · D. K. Papoulias🇬🇷 · Rahul Srivastava🇮🇳

   We explore the prospect of constraining light mediators at the next generation direct detection dark matter detectors through coherent elastic neutrino-nucleus scattering (CE$\nu$NS) and elastic neutrino-electron scattering (E$\nu$ES) measurements. Taking into account various details like the quenching factor corrections, atomic binding effects, realistic backgrounds, detection efficiency, energy resolution etc., we consider two representative scenarios regarding detector specifications. For both scenarios, we obtain the model-independent projected sensitivities for all possible Lorentz-invariant interactions, namely scalar ($S$), pseudoscalar ($P$), vector ($V$), axial vector ($A$) and tensor ($T$). For the case of vector interactions, we also focus on two concrete examples: the well-known $U(1{)}_{B-L}$ and $U(1{)}_{L_{\mu }-L_{\tau }}$ gauge symmetries. For all interaction channels $X=\{S,P,V,A,T\}$, our results imply that the upcoming dark matter detectors have the potential to place competitive constraints, improved by about 1 order of magnitude compared to existing ones from dedicated CE$\nu$NS experiments, XENON1T, beam dump experiments and collider probes.

   hep-phPRD(2022)·36 citations
2. 02*

   Pole position of the $a_1(1260)$ resonance in a three-body unitary framework

   Daniel Sadasivan🇺🇸 · Andrei Alexandru🇺🇸 · Hakan Akdag🇩🇪 · Felipe Amorim🇺🇸 · Ruairí Brett🇺🇸 · Chris Culver🇬🇧 · Michael Döring🇺🇸 · Frank X. Lee🇺🇸 · Maxim Mai🇺🇸

   Masses, widths, and branching ratios of hadronic resonances are quantified by their pole positions and residues with respect to transition amplitudes on the Riemann sheets of the complex energy-plane. In this study we discuss the analytic structure in the physical energy region of three-body scattering amplitudes on such manifolds. As an application, we determine the pole position of the $a_1(1260)$ meson from the ALEPH experiment by allowing for $\pi \rho$ coupled channels in S- and D-wave. We find it to be $\sqrt{s_0}=(1232_{-0-11}^{+15+9}-i266_{-22-27}^{+0+15})\text{MeV}$.

   hep-phnucl-exnucl-thPRD(2022)·50 citations
3. 03*

   Proton structure functions at low $x$: the Fractal distributions

   Samira Shoeibi Mohsenabadi🇮🇷 · Shahin Atashbar Tehrani🇮🇷 · Fatemeh Taghavi-Shahri🇮🇷

   In this paper, we present the extraction of the Parton Distribution Functions (PDFs) at small momentum fractions x and at the next-to-leading order (NLO) accuracy in perturbative QCD. We show that the "sea quark distribution functions" have "Fractal" or self-similar behaviour with fixed exponent at $x<0.01$. To this end, a simple parametrization for the Parton Distribution Functions and especially for the sea quarks PDFs based on the "Fractal" approach is considered. The small $x$ experimental datasets on electron-proton ($e^{-}p$) and positron-proton ($e^{+}p$) in DIS processes at HERA for the range of $1.5<Q^2<650$ ($Ge{V}^2$) and $x<0.01$ are included in this analysis. The estimations of the uncertainty in the present analysis are carried out using the standard "Hessian" method. In total, considering the overall value of ${\chi }^2/\mathrm{dof}$ and theory/data comparisons, the results indicate nice agreements between the experimental datasets and the theory predictions at small momentum fractions $x$. Finally, we present detailed comparisons between predictions for the relevant small-$x$ observables obtained with various recent models of proton PDFs available in literature.

   hep-phInt.J.Mod.Phys.A(2023)·3 citations
4. 04*

   BSM Cosmology from BSM Physics

   Maxim Yu. Khlopov🇷🇺

   Now Standard $\Lambda$CDM cosmology is based on physics Beyond the Standard Model (BSM), which in turn needs cosmological probes for its study. This vicious circle of problems can be resolved by methods of cosmoparticle physics, in which cosmological messengers of new physics provide sensitive model dependent probes for BSM physics. Such messengers, which are inevitably present in any BSM basis for now Standard cosmology, lead to deviations from the Standard cosmological paradigm. We give brief review of some possible cosmological features and messengers of BSM physics, which include balancing of baryon asymmetry and dark matter by sphaleron transitions, hadronic dark matter and exotic cosmic ray components, a solution for puzzles of direct dark matter searches in dark atom model, antimatter in baryon asymmetrical Universe as sensitive probe for models of inflation and baryosynthesis and its possible probe in AMS02 experiment, PBH and GW messengers of BSM models and phase transitions in early Universe. These aspects are discussed in the general framework of methods of cosmoparticle physics.

   hep-phastro-ph.COastro-ph.HE0 citations
5. 05*

   Sum rule for the partial decay rates of bottom hadrons based on the dynamical supersymmetry of the $\bar{s}$ quark and the $ud$ diquark

   Taiju Amano🇯🇵 · Daisuke Jido🇯🇵 · Stefan Leupold🇸🇪

   We investigate the weak decays of ${\bar{B}}_s^0$ and ${\Lambda }_b$ to charm hadrons based on the dynamical supersymmetry between the $\bar{s}$ quark and the $ud$ diquark. We derive a new sum rule relating the decay rates of the processes ${\bar{B}}_s^0\to D_s^{+}{P}^{-}$, ${\bar{B}}_s^0\to D_s^{\ast +}{P}^{-}$ and ${\Lambda }_b\to {\Lambda }_c{P}^{-}$, where $P^{-}$ is a negatively charged meson, such as ${\pi }^{-}$ and $K^{-}$. It is found that the observed decay rates satisfy the sum rule very well. This implies that the supersymmetry between the $\bar{s}$ quark and the $ud$ diquark is also seen in the wavefunctions of the heavy hadrons and suggests that the $ud$ diquark can be regarded as a valid effective constituent for heavy hadrons.

   hep-phnucl-thPRD(2022)·6 citations
6. 06*

   Loopy Determinations of $V_{ub}$ and $V_{cb}$

   Wolfgang Altmannshofer🇺🇸 · Nathan Lewis🇺🇸

   We use loop induced processes like meson oscillations and rare b hadron decays to determine the absolute values of the CKM matrix elements $|V_{ub}|$ and $|V_{cb}|$ and compare our results to the standard determinations based on inclusive and exclusive semileptonic tree-level decays of B mesons. For many years there have been tensions between the inclusive and exclusive determinations. Assuming the absence of new physics, we find that meson oscillation data shows a slight preference for the inclusive value of $|V_{cb}|$ and the exclusive value for $|V_{ub}|$. Rare b decay data prefers values for $|V_{cb}|$ far below the inclusive and exclusive determinations, offering a new perspective on some of the persistent rare b decay anomalies.

   hep-phPRD(2022)·16 citations
7. 07*

   UV/IR symmetries of the $S$-matrix and RG flow

   Silas R. Beane🇺🇸 · Roland C. Farrell🇺🇸

   The low energy $S$-matrix which describes non-relativistic scattering arising from finite-range forces has UV/IR symmetries that are hidden in the corresponding effective field theory (EFT) action. It is shown that the $S$-matrix symmetries are manifest as geometric symmetries of the RG flow of coupling constants in the EFT action in both three and two spatial dimensions. An example is given demonstrating that UV/IR symmetry breaking in the $S$-matrix implies strong constraints on the RG flow of the coefficients of the corresponding symmetry-breaking operators in the EFT.

   hep-phhep-thquant-phNPA(2022)·3 citations
8. 08*

   Self-similar behavior of the Neutron Fracture Functions

   Samira Shoeibi Mohsenabadi🇮🇷 · F. Taghavi-Shahri🇮🇷

   In this article, we have employed fractal formalism to calculate the Fracture Functions of the Leading neutron produced in \textit{ep} collisions. The fractal concept describes the self-similar behavior of the proton structure at Leading neutron production of semi-inclusive Deep Inelastic Scattering at the low values of the fractional momentum variable $\beta$. The Fracture Functions (FFs) parameterized the non-perturbative part of the fragmentation process at the initial scale of Q${}_0^2$. In this analysis, we benefit from the Leading neutron (Ln) experimental data published by H1 Collaboration and in order to estimate the uncertainty of neutron FFs and corresponding observables, we used the Hessian method. As a consequence of this Next-to-Leading order QCD analysis, we achieve a nice agreement between the prediction of our model for neutron FFs and experimental data. It seems that the fractal approach based on the self-similar behavior of these conditional parton distribution functions at low x can nicely describe the experimental data.

   hep-phInt.J.Mod.Phys.A(2022)·1 citation
9. 09*

   Production of excited heavy quarkonia in $e^{+}{e}^{-}\to {\gamma }^{\ast }/Z^0\to |(Q\bar{Q})[n]⟩+\gamma$ at super $Z$ factory

   Qi-Li Liao🇨🇳 · Jun Jiang🇨🇳 · Peng-Cheng Lu🇨🇳 · Gu Chen🇨🇳

   Within the nonrelativistic quantum chromodynamics framework, we make a comprehensive study on the exclusive production of excited charmonium and bottomonium in $e^{+}{e}^{-}\to {\gamma }^{\ast }/Z^0\to |(Q\bar{Q})[n]⟩+\gamma$ ($Q=c$ or $b$ quarks) at future $Z$ factory, where the $[n]$ represents the color-singlet $n^1{S}_0,n^3{S}_1,n^1{P}_0$ and $n^3{P}_J$ ($n=1,2,3,4;J=0,1,2$) Fock states. The "improved trace technology" is adopted to derive the analytic expressions at the amplitude level, which is useful for calculating the complicated $nP$-wave channels. Total cross sections, differential distributions, and uncertainties are discussed in system. According to our study, production rates of heavy quarkonia of high excited Fock states are considerable at future $Z$ factory. The cross sections of charmonium for $2S$, $3S$, $4S$, $1P$, $2P$, $3P$ and $4P$-wave states are about $53.5\%$, $30.4\%$, $23.7\%$, $13.7\%$, $6.8\%$, $9.2\%$, and $9.2\%$ of that of the $1S$ state, respectively. And cross sections of bottomonium for $2S$, $3S$, $4S$, $1P$, $2P$, $3P$ and $4P$-wave states are about $39.3\%$, $12.3\%$, $14.3\%$, $7.1\%$, $3.1\%$, $2.7\%$, and $3.1\%$ of that of the $1S$ state, respectively. The main uncertainties come from the radial wave functions at the origin and their derivatives at the origin under different potential models. Then, such super $Z$ factory should be a good platform to study the properties of the high excited charmonium and bottomonium states.

   hep-phPRD(2022)·10 citations
10. 10*

    $SU(3)$ breaking effects in $B$ and $D$ meson lifetimes

    Daniel King🇬🇧 · Alexander Lenz🇩🇪 · Thomas Rauh🇨🇭

    In the heavy quark expansion (HQE) of the total decay rates of $B_s$ and $D_s^{+}$ mesons non-perturbative matrix elements of four quark operators are arising as phase space enhanced contributions. We present the first determination of $m_s$ effects to the dimension six matrix elements of these four quark operators via a heavy quark effective theory (HQET) sum rule analysis. In addition we calculate for the first time eye contractions of the four quark operators as well as matrix elements of penguin operators. For the perturbative part we solve the 3-loop contribution to the sum rule and we evaluate condensate contributions. In this study we work in the strict HQET limit and our results can also be used to estimate the size of the matrix element of the Darwin operator via equations of motion.

    hep-phJHEP(2022)·51 citations
11. 11*

    Central exclusive production of axial-vector $f_1$ mesons in proton-proton collisions within the tensor-pomeron approach

    Piotr Lebiedowicz🇵🇱

    We discuss the central exclusive production of $f_1$ mesons in proton-proton collisions. The diffractive pomeron-pomeron fusion process within the tensor-pomeron approach is considered. Two ways to construct the pomeron-pomeron-$f_1$ coupling are discussed. The theoretical calculation of coupling constants is a challenging problem of nonperturbative QCD. We adjust the parameters of the model to the WA102 experimental data. The total cross section and differential distributions are presented. Predictions for LHC experiments are given. Detailed analysis of the distributions in ${\varphi }_{pp}$ the azimuthal angle between the transverse momenta of the outgoing protons can help to check different models and to study real pattern of the absorption effects.

    hep-phSciPost Phys.Proc.(2022)·1 citation
12. 12*

    Broad toplike vector quarks at LHC and HL-LHC

    Sayan Dasgupta🇮🇳 · Rohan Pramanick🇮🇳 · Tirtha Sankar Ray🇮🇳

    Top like vector quarks arising from underlying strong sectors are expected to have large decay widths pushing them beyond the narrow width approximation. In this paper we consider a broad colored vector quark that strongly couples to an exotic pseudoscalar. We use the full 1PI resummed propagator for the exotic quark to recast the present LHC constraints ruling out masses below $\sim 1.2(1.1)$ TeV for width to mass ratio of $0.1(0.6)$. We utilize machine learning techniques that are demonstratively more efficient than traditional cut based searches to present the reach of HL-LHC on the parameter space of this broad resonance. We find that at $3a{b}^{-1}$ the HL-LHC has a discovery potential up to $1.6$ TeV dominated by the pair production channel. We study the feasibility of using machine learning techniques to analyze the broad resonance peaks expected from these exotic quarks at collider experiments like the LHC.

    hep-phPRD(2022)·21 citations
13. 13*

    A new approach to dark matter from the mass-radius diagram of the Universe

    Aldo Ianni🇮🇹 · Massimo Mannarelli🇮🇹 · Nicola Rossi🇮🇹

    Modern cosmology successfully deals with the origin and the evolution of the Universe at large scales, but it is unable to completely answer the question about the nature of the fundamental objects that it is describing. As a matter of fact, about 95\% of the constituents of the Universe is indeed completely unknown: it cannot be described in terms of known particles. Despite intense efforts to shed light on this literal darkness by dark matter and dark energy direct and indirect searches, not much progress has been made so far. In this work, we take a different perspective by reviewing and elaborating an old idea of studying the mass-radius distribution of structures in the Universe in relationship with the fundamental forces acting on them. As we will describe in detail, the distribution of the observed structures in the Universe is not completely random, but it reflects the intimate features of the involved particles and the nature of the fundamental interactions at play. The observed structures cluster in restricted regions of the mass-radius diagram linked to known particles, with the remarkable exception of very large structures that seem to be linked to an unknown particle in the sub-eV mass range. We conjecture that this new particle is a self-interacting dark matter candidate.

    hep-phastro-ph.GAhep-thResults Phys.(2022)·6 citations
14. 14*

    Machine Learning in the Search for New Fundamental Physics

    Georgia Karagiorgi🇺🇸 · Gregor Kasieczka🇩🇪 · Scott Kravitz🇺🇸 · Benjamin Nachman🇺🇸 · David Shih🇺🇸

    Machine learning plays a crucial role in enhancing and accelerating the search for new fundamental physics. We review the state of machine learning methods and applications for new physics searches in the context of terrestrial high energy physics experiments, including the Large Hadron Collider, rare event searches, and neutrino experiments. While machine learning has a long history in these fields, the deep learning revolution (early 2010s) has yielded a qualitative shift in terms of the scope and ambition of research. These modern machine learning developments are the focus of the present review.

    hep-phhep-exphysics.data-anstat.ML102 citations
15. 15*

    Renormalization of the axial current operator in dimensional regularization at four-loop in QCD

    Long Chen🇩🇪 · Michał Czakon🇩🇪

    We provide the renormalization constants of the axial current operators, both singlet and non-singlet, in dimensional regularization up to four-loop order in QCD, determined using the off-shell Ward-Takahashi identity for an axial current with a non-anticommuting ${\gamma }_5$. A possible application of the result for the singlet axial current operator is the extraction of the non-decoupling mass logarithms in the axial quark form factors.

    hep-phhep-thJHEP(2022)·13 citations
16. 16*

    Determination of impact parameter in high-energy heavy-ion collisions via deep learning

    Pei Xiang🇨🇳 · Yuan-Sheng Zhao🇨🇳 · Xu-Guang Huang🇨🇳

    In this study, Au+Au collisions with the impact parameter of $0\le b\le 12.5$ fm at $\sqrt{s_{NN}}=200$ GeV are simulated by the AMPT model to provide the preliminary final-state information. After transforming these information into appropriate input data (the energy spectra of final-state charged hadrons), we construct a deep neural network (DNN) and a convolutional neural network (CNN) to connect final-state observables with impact parameters. The results show that both the DNN and CNN can reconstruct the impact parameters with a mean absolute error about $0.4$ fm with CNN behaving slightly better. Then, we test the neural networks for different beam energies and pseudorapidity ranges in this task. It turns out that these two models work well for both low and high energies. But when making test for a larger pseudorapidity window, we observe that the CNN shows higher prediction accuracy than the DNN. With the method of Grad-CAM, we shed light on the `attention' mechanism of the CNN model.

    hep-phCPC(2022)·17 citations
17. 17*

    NLO QCD Corrections to Inclusive $b\to c\ell \bar{\nu }$ Decay Spectra up to $1/m_Q^3$

    Th. Mannel🇩🇪 · D. Moreno🇩🇪 · A. A. Pivovarov🇩🇪

    We present analytical results for higher order corrections to the decay spectra of inclusive semileptonic heavy hadron weak decays using the heavy quark expansion (HQE). We compute analytically the spectrum of the leptonic invariant mass for $B\to X_c\ell \bar{\nu }$ up to and including terms of order $1/m_Q^3$ within the HQE at next-to-leading order (NLO) in ${\alpha }_s$. The full dependence of the differential rate on the mass of the final-state quark is taken into account. We discuss the implications of our results for the precision determination of the CKM matrix element $|V_{cb}|$.

    hep-phPRD(2022)·43 citations
18. 18*

    On transverse momentum broadening in real-time lattice simulations of the glasma and in the weak-field limit

    Andreas Ipp🇦🇹 · David I. Müller🇦🇹 · Daniel Schuh🇦🇹

    In these proceedings, we report on our numerical lattice simulations of partons traversing the boost-invariant, non-perturbative glasma as created at the early stages of collisions at RHIC and LHC. Since these highly energetic partons are produced from hard scatterings during heavy-ion collisions, they are already affected by the first stage of the medium's time evolution, the glasma, which is the pre-equilibrium precursor state of the quark-gluon plasma. We find that partons quickly accumulate transverse momentum up to the saturation momentum during the glasma stage. Moreover, we observe an interesting anisotropy in transverse momentum broadening of partons with larger broadening in the rapidity than in the azimuthal direction. Its origin can be related to correlations among the longitudinal color-electric and color-magnetic flux tubes in the initial state of the glasma. We compare these observations to the semi-analytic results obtained by a weak-field approximation, where we also find such an anisotropy in a parton's transverse momentum broadening.

    hep-phhep-latnucl-thEPJ Web Conf.(2022)·1 citation
19. 19*

    Beyond Jarlskog: 699 invariants for CP violation in SMEFT

    Quentin Bonnefoy🇩🇪 · Emanuele Gendy🇩🇪 · Christophe Grojean🇩🇪 · Joshua T. Ruderman🇺🇸

    As SMEFT is a framework of growing importance to analyze high-energy data, understanding its parameter space is crucial. The latter is commonly split into CP-even and CP-odd parts, but this classification is obscured by the fact that CP violation is actually a collective effect that is best captured by considering flavor-invariant combinations of Lagrangian parameters. First we show that fermion rephasing invariance imposes that several coefficients associated to dimension-six operators can never interfere with operators of dimension $\le 4$ and thus cannot appear in any physical observable at $\text{order}1/{\Lambda }^2$. For those that can, instead, we establish a one-to-one correspondence with CP-odd flavor invariants, all linear with respect to SMEFT coefficients. We explicitly present complete lists of such linear CP-odd invariants, and carefully examine their relationship to CP breaking throughout the parameter space of coefficients of dimension $\le 4$. Requiring that these invariants all vanish, together with the Jarlskog invariant, the strong-CP phase, and the 6 CP-violating dimension-6 bosonic operators, provides $699(+1+1+6)$ conditions for CP conservation to hold in any observable at leading order, \cO\(1/\Lambda^2\).

    hep-phhep-exhep-thJHEP(2022)·43 citations
20. 20*

    Event topology and global observables in heavy-ion collisions at the Large Hadron Collider

    Suraj Prasad🇮🇳 · Neelkamal Mallick🇮🇳 · Debadatta Behera🇮🇳 · Raghunath Sahoo🇮🇳 · Sushanta Tripathy🇮🇹

    Particle production and event topology are very strongly correlated in high-energy hadronic and nuclear collisions. Event topology is decided by the underlying particle production dynamics and medium effects. Transverse spherocity is an event shape observable, which has been used in pp and heavy-ion collisions to separate the events based on their geometrical shapes. It has the unique capability to distinguish between jetty and isotropic events. In this work, we have implemented transverse spherocity in Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5.02 TeV using A Multi-Phase Transport Model (AMPT). While awaiting for experimental explorations, we perform a feasibility study of dependence of transverse spherocity on some of the global observables in heavy-ion collisions at the Large Hadron Collider energies. These global observables include the Bjorken energy density (${ϵ}_{{\mathrm{B}}_{\mathrm{j}}}$), speed of sound ($c_{\mathrm{s}}^2$) in the medium and the kinetic freeze-out properties for different collision centralities. The present study reveals about the usefulness of event topology dependent measurements in heavy-ion collisions in contrast to proton-proton collisions.

    hep-phhep-exnucl-exnucl-thSci.Rep.(2022)·34 citations
21. 21*

    Maximizing Direct Detection with Highly Interactive Particle Relic Dark Matter

    Gilly Elor🇩🇪 · Robert McGehee🇺🇸 · Aaron Pierce🇺🇸

    We estimate the maximum direct detection cross section for sub-GeV dark matter (DM) scattering off nucleons. For DM masses in the range $10\text{ keV }-100\text{ MeV}$, cross sections greater than $10^{-36}$- $10^{-30}{\text{cm}}^2$ seem implausible. We present a DM candidate which realizes this maximum cross section: HighlY interactive ParticlE Relics (HYPERs). After HYPERs freeze-in, a dark sector phase transition decreases the mediator's mass. This increases the HYPER's direct detection cross section without impacting its abundance or measurements of Big Bang Nucleosynthesis and the Cosmic Microwave Background.

    hep-phhep-exPRL(2023)·119 citations
22. 22*

    Twisted Superfields

    Scott Chapman🇺🇸

    A model is presented that could lead to an interesting extension of the Standard Model. Like a supersymmetric gauge theory, the model is holomorphic and invariant to local superspace gauge transformations. However, the model is not invariant to superspace translations, so it is not supersymmetric. It is proposed that this combination allows the model to have many of the attractive features of supersymmetric theories, while at the same time predicting fewer particles that have not yet been seen experimentally. For example, the ``superpartners'' of the gauge bosons in the model are quarks. The model is able to generate the symmetries and particles of the Standard Model, but with some significant differences that have observable consequences. These consequences provide possible explanations for a number of 3-7 sigma deviations from Standard Model calculations that have been found in recent experiments.

    hep-phhep-th3 citations
23. 23*

    Some Recent Results on Renormalization-Group Properties of Quantum Field Theories

    Robert Shrock🇺🇸

    We discuss some higher-loop studies of renormalization-group flows and fixed points in various quantum field theories.

    ↳ hep-thhep-lathep-phSciPost Phys.Proc.(2022)·1 citation
24. 24*

    Fate of Multiparticle Resonances: From $Q$-Balls to ${}^3$He Droplets

    Dam Thanh Son🇺🇸 · Mikhail Stephanov🇺🇸 · Ho-Ung Yee🇺🇸

    We consider a system of $N$ nonrelativistic particles which form a near-threshold resonance. Assuming no subset of these particles can form a bound state, the resonance can only decay through an "explosion" into $N$ particles. We show that the decay width of the resonance scales as $E^{\Delta -5/2}$ in the limit when the energy $E$ of the resonance goes to zero, where $\Delta$ is the ground state energy of a system of $N$ particles in a spherical harmonic trap with unit frequency. The formula remains valid when some pairs of final particles have zero-energy $s$-wave resonance, but the Efimov effect is not present. In the limit of large $N$, we show that the final particles follow a Maxwell-Boltzmann distribution if they are bosons, and a semicircle-like law if they are fermions. We argue that metastable ${}^3$He droplets exist with the lifetime varying over many orders of magnitudes ranging from a fraction of a nanosecond to values greatly exceeding the age of the Universe.

    ↳ nucl-thcond-mat.quant-gashep-phmath-ph+1PRA(2022)·10 citations
25. 25*

    Higher-order transverse momentum fluctuations in heavy-ion collisions

    Somadutta Bhatta🇺🇸 · Chunjian Zhang🇺🇸 · Jiangyong Jia🇺🇸

    In relativistic heavy-ion collisions, the event-by-event mean transverse momentum fluctuations are sensitive to overlap area and energy density fluctuations in initial state. We present a framework to calculate $p_{\mathrm{T}}$ fluctuations up to $4^{\mathrm{th}}$-order using standard and subevent methods, which is validated using the HIJING model. We observe a power-law dependence for cumulants of all orders as a function of charged particle multiplicity $N_{\mathrm{ch}}$, consistent with a simple independent source picture. The fluctuation in $pp$ collisions is observed to be larger than for $p+$Pb, Pb+Pb and Xe+Xe collisions at the same $N_{\mathrm{ch}}$ due to bias in number of contributing sources. The short-range correlations are greatly suppressed in subevent method in comparison to calculations based on the standard method. This study provides a baseline for transverse momentum fluctuations without the presence of final state effects.

    ↳ nucl-thhep-phnucl-exPRC(2022)·24 citations
26. 26*

    Cutting Rule for Cosmological Collider Signals: A Bulk Evolution Perspective

    Xi Tong🇨🇳 · Yi Wang🇨🇳 · Yuhang Zhu🇨🇳

    We show that the evolution of interacting massive particles in the de Sitter bulk can be understood at leading order as a series of resonant decay and production events. From this perspective, we classify the cosmological collider signals into local and nonlocal categories with drastically different physical origins. This further allows us to derive a cutting rule for efficiently extracting these cosmological collider signals in an analytical fashion. Our cutting rule is a practical way for extracting cosmological collider signals in model building, and can be readily implemented as symbolic computational packages in the future.

    ↳ hep-thastro-ph.COgr-qchep-phJHEP(2022)·81 citations
27. 27*

    Shock Revival in Core-collapse Supernovae Assisted by Heavy Axion-like Particles

    Kanji Mori🇯🇵 · Tomoya Takiwaki🇯🇵 · Kei Kotake🇯🇵 · Shunsaku Horiuchi🇺🇸

    Axion-like particles (ALPs) are a class of hypothetical pseudoscalar particles which feebly interact with ordinary matter. The hot plasma of core-collapse supernovae is a possible laboratory to explore physics beyond the standard model including ALPs. Once produced, some of the ALPs can be absorbed by the supernova matter and affect energy transfer. In this study, we calculate the ALP emission in core-collapse supernovae and the backreaction on supernova dynamics consistently. It is found that the stalled bounce shock can be revived if the coupling between ALPs and photons is as high as g_{ag}~10^{-9} GeV^{-1} and the ALP mass is 40-400 MeV. Most of the models result in more energetic explosions than the average observed supernova. While this can be used to place constraints on those ALPs, long-term simulations across multiple progenitors need to be further investigated to place robust limits.

    ↳ astro-ph.HEhep-phPRD(2022)·23 citations
28. 28*

    Constraining Primordial Black Hole Dark Matter with CHIME Fast Radio Bursts

    Keren Krochek🇮🇱 · Ely D. Kovetz🇮🇱

    Strong lensing of Fast Radio Bursts (FBRs) has been proposed as a relatively clean probe of primordial black hole (PBH) dark matter. Recently, the Canadian Hydrogen Intensity Mapping Experiment (CHIME) published a first catalog of 536 FRBs, 62 of which are from repeating sources. In light of this new data, we re-examine the prospects to constrain the abundance of PBHs via FRBs. Extending previous forecasts, we calculate a PBH dark matter bound using the intrinsic burst width and a calibrated flux-ratio threshold per FRB. In addition, we take into account the uncertainty in the relation between the FRB dispersion measure and source redshift. We outline an algorithm to detect lensed FRBs and a method to simulate its performance on real data and set a flux-ratio threshold for each event, which we use to infer realistic forecasts. We then attempt to extract a preliminary bound using the publicly available CHIME data. Unfortunately, both instrumental noise and the provided ~1 ms time-resolution of the public data hinder this effort. We identify one candidate event where a double burst could be explained via strong lensing by a 10 solar-mass PBH, which will require follow-up study at higher time resolution to either confirm or discard. We show that with a few times the size of the first catalog -- sampled at the full instrumental time-resolution so that candidates can be efficiently scrutinized -- CHIME will be able to find strong evidence for or robustly rule out PBHs with mass above 10 solar masses as the dark matter. Finally, we demonstrate that stacking repeating FRBs can improve the constraints, especially for lower masses.

    ↳ astro-ph.COastro-ph.HEhep-phPRD(2022)·20 citations
29. 29*

    Islands and the de Sitter entropy bound

    Daniele Teresi🇨🇭

    The de Sitter (dS) entropy bound gives the maximal number of e-folds that non-eternal inflation can last before violating the thermodynamical interpretation of dS space. This semiclassical argument is the analogue, for dS space, of the Black-Hole information paradox. We use techniques developed to address the latter, namely the island formula, to calculate semiclassically the fine-grained entropy as seen by a Minkowskian observer after inflation and find that this follows a Page-like curve, never exceeding the thermodynamic dS entropy. This calculation, performed for a CFT in 2D gravity, suggests that the semiclassical expectation should be modified in such a way that the entropy bound might actually not be present.

    ↳ hep-thhep-phJHEP(2022)·20 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.